Contractility, with preload, afterload and heart rate, is one of the four elements determining cardiac output. It describes the ability of the heart to contract at a given fibre length and in absence of any change in preload or afterload; it refers to the inherent property of shortening of myocardial muscle fibers and it is sometimes indicated as heart inotropy. We can imagine it as the “power” of cardiac muscle, suggesting the quality of its performance.

Multiple factors influence heart contractility; the main one is the sympathetic nervous system.

Heart contractility increases when norepinephrine are released by nerve endings; a similar effect is obtained with epinephrine (adrenaline) and drugs such as ephedrine, digoxin, calcium administration.

Heart contractility reduction is obtained in case of acidosis, myocardial ischemia, beta-blocking and anti-arrhythmic agents.

Heart contractility dynamically changes so to compensate body metabolic demand.

The measurement of myocardial performance is of critical importance for diagnosis and management of the patient with cardiac disease[1]. Despite decades of investigation, the search for the optimal method to measure the contractile properties of the myocardium still continues; difficulties in obtaining an accurate index has been clearly reported[2]. Extrapolations from experiments in isolated muscle preparations and the intact animal heart have resulted in invasive measurements of myocardial function such as peak positive dp/dt, cardiac output, and maximal elastance[3]-[4]-[5].

dP/dtmax, calculated as the peak rate of left ventricular (LV) pressure development (dP/dt max), has originally been measured directly in left ventricle; left ventricle catheterization with a high fidelity pressure catheter is necessary at this purpose and hence it is not common in clinical practice[6].

MostCare, the mininvasive haemodynamic monitoring device, provides a parameter giving an indirect description of heart contractility; calculating the maximal ascending slope of the peripheral arterial pressure curve (dP/dtmax),  Vytech device offers some more elements to doctors evaluation.